New Nanomaterial to Remove CO2 From Power Plant Emissions

Researchers from the University of Adelaide have developed a new nanostructured metal-organic framework which could be used to remove carbon dioxide from power plant flue gases, significantly reducing greenhouse gas emissions from electricity generation.

Coal-fired power plants are one of the biggest sources of electricity, and one of the biggest sources of greenhouse gases. Image credit: Morguefile.com.

The material, reported in the Journal of the American Chemical Society in June, is a novel metal-organic framework, based on copper ions linked together by a regular crystalline network, made of an organic molecule called BCPPM.

This crystalline network contains tiny pores, which are ideal for absorbing gases. Metal-organic frameworks (MOFs) are quite likely to contain pores which are a similar size to molecules, which has made them the subject of a great deal of research in fields such as gas storage, catalysis, and molecular separation.

The pores in this material are just barely big enough to contain molecules of carbon dioxide, and contain binding sites which hold the molecules inside. These binding sites have little effect on nitrogen molecules, making the pores extremely selective. This gives them a clear practical application - removing CO2, a major greenhouse gas, from the hot air (primarily nitrogen) which is released from fossil fuel power stations.

The team from the University of Adelaide, led by Associate Professor Christopher Sumby, has successfully demonstrated the efficacy of their material at removing CO2 from a gas. They will now be working on adapting the technology for industrial use. Professor Sumby commented:

"This material could be used as it is but there are probably smarter ways to implement the benefits. One of the next steps we're pursuing is taking the material in powder form and dispersing it in a membrane. That may be more practical for industrial use."

Professor Sumby suggested that this technology could be used to reduce emissions from fossil fuel power plants as a short-term measure, giving cleaner advanced energy technologies time to mature:

"A considerable amount of Australia's - and the world's - carbon dioxide emissions come from coal-fired power stations, so removing CO2 from the flue gas mixture is the focus of a lot of research. Changing to cleaner energies is not that straightforward but, if we can clean up the emissions, we've got a great stop-gap technology."

This would certainly give the energy industry some breathing space, and allow countries like Australia who rely heavily on fossil fuels to meet greenhouse gas emissions targets more easily.

This is not a permanent solution, however, and other technologies need to be developed in parallel in order for large-scale adoption to work.

For example, all the CO2 which is produced is still there - it may not be released directly to the atmosphere, but storage or sequestration methods would need to be employed on a large scale. CCS (carbon capture and sequestration) technology is still largely in its infancy, although some large-scale demonstration projects have sprung up in the last few years.

Despite this, it is extremely encouraging to see such potential for reducing carbon emissions from power plants, and certainly any effective stop-gap measures will be welcomed by the industry.

They are smaller, yes - the pores in the MOF actually have a good affinity for CO2 adsorption, and a very low affinity for N2. From the JACS paper, the uptake was 590 times greater for CO2 than for nitrogen, for a 15% CO2 gas stream at standard temperature and pressure.

The statement was taken from the original news release from the University of Adelaide, and this article has been updated now.